The present invention generally relates to telecommunications and more specifically to recovering a clock of a transmitter at a receiver.
In a packet switched network (PSN), a transmitter node may receive a serial bitstream from a local source, packetize it (i.e., chop the continuous stream into groups of bits), add packet headers/trailers, and send the packets across a packet switched network. The packets are received at a receiver node. The receiver node stores the incoming packets (or the packets' payload) in a buffer, and then reads the data of the payload out and plays a serial stream of the data locally to an attached serial stream receiver. At the sender end, the serial bitstream is played at a fixed rate of X bits per second (Mbps). The packets do not carry the timing of the serial bitstream. While traversing the PSN, jitter or packet delay variation (PDV) may be introduced to the packet stream. Accordingly, the packets may arrive at the receiver node in varying intervals.
The information in the packets is then arranged into the serial bitstream and played out to the local serial receiver. In playing out the serial bitstream, a clock needs to be used to play the serial bitstream at a certain fixed rate. This clock should be the same rate as the clock used to send the packets at the sender end. The fixed rate, however, is not carried in the packets.
Accordingly, techniques for recovering a clock used at the sender's end are desired.